text: //===----------------------------------------------------------------------===//
  //
  // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
  // See https://llvm.org/LICENSE.txt for license information.
  // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
  //
  //===----------------------------------------------------------------------===//
  
  // UNSUPPORTED: c++03, c++11, c++14, c++17
  // UNSUPPORTED: libcpp-no-concepts
  // UNSUPPORTED: libcpp-has-no-incomplete-ranges
  
  // template<class R>
  // concept __nothrow_forward_range;
  
  #include <memory>
  
  #include "test_iterators.h"
  #include "test_range.h"
  
  // Has to be a template to work with `test_range`.
  template <typename>
  struct ForwardProxyIterator {
    using value_type = int;
    using difference_type = int;
    ForwardProxyIterator& operator++();
    ForwardProxyIterator operator++(int);
    bool operator==(const ForwardProxyIterator&) const;
  
    int operator*() const;
  };
  
  static_assert(std::ranges::__nothrow_forward_range<test_range<forward_iterator>>);
  static_assert(!std::ranges::__nothrow_forward_range<test_range<cpp20_input_iterator>>);
  static_assert(std::ranges::forward_range<test_range<ForwardProxyIterator>>);
  static_assert(!std::ranges::__nothrow_forward_range<test_range<ForwardProxyIterator>>);
  
  constexpr bool forward_subsumes_input(std::ranges::__nothrow_forward_range auto&&) {
    return true;
  }
  constexpr bool forward_subsumes_input(std::ranges::__nothrow_input_range auto&&);
  
  static_assert(forward_subsumes_input("foo"));
  